1293124 九、發明說明： 【發明所屬之技術領域】 本發明涉及一種磁感測器的信號檢測電路，特別是一 種用來提供具有高精度與穩定性的磁感測器的信號檢測電 路的技術。 5 【先前技術】 有一種公知的所謂的磁通量閘門磁力計，其通過給纏 繞在軟磁性鐵心（c〇re)上的勵磁線圈輸入週期的驅動信 號，讓磁通量週期性飽和，根據對應於作為測定物件的外 10部磁場之大小進行變化的飽和時間間隔，來測定外部磁場 的強度。磁通量閘門磁力計，作為磁力計具有各種優秀的 特徵：（1)靈敏度以及磁場解析度較高、（2)能夠測定 微弱的磁場、（3)測定範圍廣、（4)與其他方式的磁力 計相比溫度穩定性較好、（5)對輸入磁場的直線性高。 15 作為這樣的磁通量閘門磁力計之一例，專利文獻1中 公開了:種磁力計’其具有通過載入給勵磁線圈的交流信 號的通電’將磁檢測材料所構成的環形鐵心勵磁到飽和磁 坊的區域’利用環形鐵心中所激勵的飽和磁通量密度的對 稱來測量磁通量密度的磁感測器。另外，專利文獻2 20中公開了 一種通過振盪器給在鐵心中纏繞勵磁線圈與檢測 線圈所構成的磁通量閘門的勵磁線圈載入激勵電流，通過 同步整，電，檢測線圈的輸出進行同步整流並輸出的磁 力计。最近遂期待應用於可攜式指南針用磁感測器等小型 機器中。 5 1293124 於出j 磁t量目贈^磁力計的磁感測器的對檢測線圈的 輸出信號檢測電路， 性。另外’在對多個空間軸方向進行=;疋 通常將多個磁通量閘門磁力計並用，各個磁力 造偏差較小。進 在積體化時不占晶片面積。 專利文獻1」特開2GG5— 147947號公報 「專利文獻2」特開平8-285929號公報 「專利文獻3」特開2〇〇5 —㈣的號公報 【發明内容】 本發明鑒於以上問題，目的在於提供一種 與穩定性，製造偏差較小且萨焱丨/、肩同積度 檢測電路。 W ^夠小型化的磁感測器的信號 15 用來實社述目的的本發日种社要發明，是— 感測器的信號檢測電路，其特徵在於，且有 έ 感測器的檢測線圈的輸出電壓的差動放大器；比較哭^ 被輸入上縣減大器的輸出，輸出在分職出了二二 出電壓中所含㈣相__尖峰狀電壓之間，取 邏輯值的數位信號；以及計數器，其在上述比較^ 取得-方邏輯值_間中，計數時鐘的脈衝數。-輪出 =樣’本發明的磁感·的信號檢測電路，通 鐘的脈衝數進行計數，紐地啦檢測線= 笔壓中所含㈣相鄰的兩個尖錢龍的時間 ^出 20 1293124 能夠進行高精度的磁場測定。另外，通過使用計數器來代 替類比電路，還能夠在短時間内進行測定。另外，:於磁 ==出電磨立刻觸比較器所數位化，因此很難 度或雜訊的影響。另外，輸出電壓的放大由差動放 5 因此共態雜訊一… 中靖要發明之—’是―種根據 已圍弟1項所述的磁感測器的信號檢測電路，具 川檢二圏相連接’選擇成為檢測對象的上述 15 ^ 迕偏明’能夠提供一種具有高精度與穩定性，穿 攻偏差較小且能夠小型化的磁感測器的信號檢測電路。衣 【實施方式】 下面對本發明的實施方式詳細 20出了作為本發明的—實施方式進行說明=、sr圓中示 計之構成。圖中所示的磁通量閉門磁力 γ轴，各個轴的3個磁感測器; 感測器U、12、U通過在夺米沾12、13。這些磁 軟磁性材料所構成的磁性體鐵心1U、二晶軟磁性材料等 121、131上纏繞勵 7 1293124 磁線圈112、122、132以及檢測線圈113、123、133而構 ’ 成。勵磁線圈m、m、132，由包含有勵磁侧開關電路 2卜同相放大器22、反相放大器23、變換器24、以及 控制D/A變換器24的動作的控制邏輯（以 c • 5制邏輯25)所構成的勵磁線圈驅動電路驅動。另外，檢測 線圈113、123、133的輸出電壓，由信號檢測電路來處理， 肺號檢測f路包含有檢測侧_電路3丨、將輸出電壓調 # f為給定電壓電平的電壓調整電路32、放大輸出電壓的差 動放大器33、在輸出電壓中所含有的兩個尖峰（spike)狀 ⑴電壓間的期間中輸出低（L0W)冑平的數位信號的磁滞比 較盗34、以及對輯比㈣34所輸出的數位信號為低電平 的期間中的時鐘信號的脈衝數進行計數的計數器％。 >，制電路41控制DAC控制邏輯25。控制電路41接收 撞盗35所輸人的計數值’並將其存健在内部的記憶體 丨5 411 控制電路41中連接有勵磁側開關電路21以及檢測 # 觸關電路31的控制線5卜控制電路41通過控制線51 對開關21錢開關31的接通斷開進行控制。控制電路41 ^匯流排61與微型電腦71 (外部裝置）可通信連接，將記 L體411中所存儲的計數值適當發送給微型電腦。 20 第二圖為表示本實施方式的磁通量閘門磁力計1之動 作的日守序圖。下面根據該圖中所示的時序圖，對磁通量閘 門磁力計1的動作進行說明。另外，以下的說明中，將勵 磁側開關電路21以及制俯電路31的所有接點預先 設為打開（斷開）。 8 1293124 如第二圖所示，首先從微型電腦71經匯流排61給控 制電路41輸人測定開始信號⑻。輸人了測定開始信號 之後，控制電路41接下來輪出用來將勵磁側開關電路21 以及檢測側開關電路31與X軸的接點接通的信號（以下稱 :5作X轴選擇信號）（t2)。輸入了 X軸選擇信號之後，勵 磁側開關電路21以及檢測側開關電路31，將用來測定χ 軸方向的磁場的磁感測為11的勵磁線圈112以及檢測線圈 φ Π3的接點接通。這樣，通過勵磁侧開關電路21來選擇載 入後述的驅動信號p以及驅動信號N的勵磁線圈112、 ίο 122、132。 接下來，控制電路41給DAC控制邏輯25輸出驅動開 始使能（enable)信號（t3) 〇DAC控制邏輯25被輸入了 驅動開始使能信號之後，給D/A變換器24輸入DAC資料。 具體地說，首先輸入倒計（down count)資料作為DAC資 μ料（t4〜t5)。通過倒計數據，將用來防止勵磁線圈112中 φ 產生給同相放大器22以及反相放大器23等電路元件帶來 損傷的高壓反電動勢的信號，在即將到後述的升壓期間之 前載入。接下來，DAC控制邏輯25將正計（upc〇unt)資 料作為DAC資料輸出給D/A變換器24 (t5)。通過這樣， 從D/A變換器24輸出三角波的升壓期間的信號（t5〜t8)。 接下來，DAC控制邏輯25在t8中停止對D/A變換器 24的正計數據的輸出，此次輸出倒計數據。通過這樣，從 D/A變換器24輸出三角波的降壓期間的信號（t8〜ul)。 接下來，DAC控制邏輯25在tll中停止對d/a變換器％ 9 !293124 的倒計數據的輸出，輸出正計數據。通過該倒計數據，將 用來防止勵磁線圈中產生給同相放大器22以及反相放大器 23等電路元件帶來損傷的高壓反電動勢的信號，在上述^ 壓期間之後立刻載入。 D/A變換器24的驅動信號，供給給同相放大器22的 同相輸入端子。D/A變換器24的Vref信號供給給反相放大 器23的同相輸入端子。同相放大器22的反相輸入端子中， 被負反饋同相放大器22的輸出。另外，反相放大器23的 反相輸入端子，被輸入了同相放大器22的輸出。通過這樣， 10從同相放大器22輸出將D/A變換器24的輸出信號進行了 放大的第二圖中通過實線所示的信號（以下稱作驅動信號 P)，另外，從反相放大器23輸出將驅動信號P的振幅進 行了反相的第二圖中通過虛線所示的信號（以下稱作驅動 信號N)。 15 同相放大器22所輸出的驅動信號P，載入給勵磁線圈 112的兩個端子中之一。另外，從反相放大器23所輸出的 驅動信號N，載入給勵磁線圈112的兩個端子中的另一端。 因此，勵磁線圈112中被載入了驅動信號P與驅動信號N 的差分電壓（以下將該電壓稱作勵磁電壓）。 20 如第二圖所示，檢測線圈113的端子間所產生的尖峰 狀電壓（t7、tlO)，是基於磁感測器n的B —H曲線（b : 磁通密度，H:磁場）中的非飽和區間中所生成的電動勢的 電壓。t7、tlO中的兩個尖峰狀電壓的時間間隔（Τχ)，對 應於磁感測器11中所載入的外部磁場△11進行變化。也 10 1293124 '’通過測定輪出兩個尖峰狀電壓的時間間隔（Τχ)，能 夠得=關於外部磁場ΔΗ的強度等的資訊。 “榀測線圈113中所產生的尖峰狀電壓，通過電壓調整 電路32、交換成了給定的電平之後，輸入給差動放大器33 :5並放大。由差動放大器33放大過的輸出電壓，輸入給磁滯 比較器34。 磁滞比較器34，輸出在輸出電壓中所含有的相鄰的尖 學狀電壓所夾持的期間中為低電平，在此外的期間中為高 (fgh)電平的數位信號。初始狀態中，磁滯比較器“輸 1〇 ^=甩平。之後，磁滯比較器34在被輸入了因t6中的勵磁 電壓的極性反相所引起的尖峰狀電壓時，開始低電平的輸 出（t7)。另外，磁滯比較器34,在被輸入了因⑸中的勵 磁電壓的極性反相所引起的尖峰狀電壓時，將輸出切 高電平（tlO)。 、 磁卬比車父态34所輸出的數位信號，輸入給計數器35。 ：§十數器35中被輸入了時鐘信號，計數器35對磁滞比較器 :34所輸出的數位信號變為低電平的期間中的時鐘信號的脈 衝數進行計數。數位信號變為高電平，結束了脈衝^輯 數之後，計數器35將計數值輸出給控制電路41。控制命 20 41將所輸入的計數值存儲在記憶體411中。 接下來’控制電路41將輸入給DAc控制邏輯25的 動開始使能信號截止（tl3)。另外，控制電路41停止勵 磁側開關電路21以及檢測側開關電路31的χ軸琴俨 的輸入（U4)。通過這樣，將用來測定“料二二 1293124 磁感：器：的勵磁線圈U2以及檢測線圈113的接點 乂及二二控制電路41輸出用來將勵磁側開關電略Yl )(tl5)。通過這樣開始對γ軸的處Ϊ Γ二Γ的期間中所進行的對Y轴的處理，邀X紐 ==r°M，tl7〜t18的期間中所進行的ί 轴的處理，也與χ轴的情況一樣進行。 訝Ζ 通過以上操作將對X轴、γ #、7 記憶體4U中之後，接下史:，二轴、Z軸的植值存餘到 寫入完成的中斷仲，發从Γη電路41將通知計數值的 通過這樣，由彳發送讀出請求。 體4n中的八侧H 存儲在控制電路41的記憶 :外^ 15 的強度測”賤。 _，提縣料磁場ΔΗ 二上所說:月的結構所構成的本實施方式的磁通 ^4的數/千1 ’由稱作DAC控制邏輯25以及D/A變換 时24的數位祕生成用來驅動勵磁線m的 信號。因此，與使賴比電路的情响比， ί=1，Γ生成高精度且穩定的驅動信號:另外，通 過使用數位電路還能夠抑制造偏差。 另外，本實施方式的磁通量間門磁力計i中，多個勵 磁=圈112、122、132由同一個D/A變換器24驅動。因此 能夠給勵磁線圈112、122、132分別載人均勻的勵磁電麼， 12 20 1293124 =輪出的偏差。另外，通過讓電路共通化，在積體化時 遇能夠削減零部件的數目以及晶片面積。 “另外本貫施方式的磁通量閘門磁力計1，通過使用數 電路此夠讓驅動號的升壓期間（6〜化）與降壓期間 (t8〜til)的長度高精度一致，從而能夠提高測定精度。 =要，如為了對時間間隔（Tx、Ty、Tz)中所含有的誤 声二=隔的影響進行修正，而測定驅動信號全體的長 在類比電路的情況下必需的電路，通過這樣， 月b 1現小型且低消耗功率的磁通量間門磁力計1。 另外，本實施方式的磁通量閘門磁力計1，通過计數哭 =日==__行計數’來測定兩個尖峰狀電i 相比，) 與使用類比電路的情況 b夠進仃咼精度的測定。另外 時間間隔（TX、Ty、Tz)…日丨—μ ^舰⑦路進订 15 20 時需要Β片 的測疋的^況下，通常在積體化 日日片佔有面積較大的a/d變換器 佔有面積較小的計數〶 崎使用曰曰片 磁力計i。 °° ，而此夠貫現小型的磁通量閑門 (Tx、T卜y、t = 波與濾波的組合進行時間間隔 精確度需要毅n H通常絲巾，為了提高測定值的 ^在⑽内進行峡。另外，這樣還抑制了魏 另外’本實施方式的磁通量閘門磁力計 滯比較器33將檢測線圈U3 123 通過磁 間113、123、133的輸出電壓在早期 13 1293124 數位化，因此很難受到溫度或雜訊的影響。 另外，本實施方式的磁通量閘門磁力計丨中，對多個 檢測線圈113、123、133的輪出電壓的處理，通過同一個 差動放大器33以及同一個磁滞比較器34來進行，因此各 :5個檢測線圈Π3、123、133間的測定值的偏差較小。另外， 通過像這樣使用同一個電路來進行檢測線圈113、123、133 的輸出電壓的處理，在積體化時能夠削減零部件數目與晶 • 片面積。 ”曰曰 另外，本實施方式的磁通量閘門磁力計丨中，輸出電 10壓的放大使用差動放大器33，因此共態雜訊（口毛y七_ F /彳久）的混入較少。另外，檢測線圈113、123、 均沒有接地，通過這樣也能夠抑制共態雜訊的混入。 以上，對本發明的一實施方式進行了詳細說明，但以 上的實施方式的說明僅僅用來讓本發明容易理解，而並不 ^對本發明進行限定。本發明能夠在不脫離其要點的範圍内 • 進行變更、改良，同時本發明還包括其等價物。例如，可 以在D/A變換器24的後段設置低通濾波器，將變換 器24所輸出的驅動信號平滑化。 另外’驅動信號的生成，還可以代替D/a變換器24， 2〇例如通過第三圖中所示的結構所組成的Sc (開關電容器） 積分器來生成。如圖所示的SC積分器80,由4個開關SW1 〜SW4、電容器C1、以及使用運算放大器的積分電路81 構成。開關SW卜電容器cn、以及SW4按順序串聯起來， swi與直流電源vin相連接，SW4的輸出輸入給構成積分 14 1293124 電路81的運算放大器的反相輸入端 55 P1 ^ BS 4. 開關SW1舆電容 之間，連接有一端接地的開關SW2。電容哭C1仙 關SW4之間’連接有—端接地的開關SW3。w八讦 在通過第三圖的sc積分器8〇生成在由 的驅動信號的升壓期間中的信號的情 ' =4以-疋間隔M進行接通斷開（极行（⑽⑹ 15 =)，交互變為第四圖U)、⑴所示的狀態。通過這 t如第=圖u)所示，能夠得到以—定的斜率階雜升 ι、驅動“號。另外，在生成驅動信號的降壓期間中的作 號的情況下，開關SW1〜SW4以-定間隔At2進行接通斷 開（蝶形驅動方式），交互變為第五圖（a)、（b)所示 的狀態。通過這樣，如第六圖（b)所示，能夠得到以一定 的斜率階梯狀降壓的驅動信號。另外，SC積分器80所輸 出的驅動信號，從低通濾波器令通過並被平滑化，從而能 夠得到直線狀的驅動信號。 上述SC積分器80中，能夠使用公知的數位電路讓a ti與Δί2準確地一致，從而能夠生成升壓期間與降壓期間的 斜率高精度一致的準確的三角波。因此，即使在使用SC積 分器80的情況下，也和D/A變換器24的情況相同，能夠 實現一種可高精度進行磁場測定的磁通量閘門型磁力計1。 15 20 1293124 【圖式簡單說明】 第一圖為表示作為本發明的一實施方式進行說明的磁 通量閘門磁力計1之結構的圖。 第二圖為表示作為本發明的一實施方式進行說明的磁 5 通量閘門磁力計1之動作的時序圖。 第三圖為表示作為本發明的一實施方式進行說明的 SC積分器80之一例的圖。 • 第四圖（a)、（b)為表示生成驅動信號的升壓期間 中的信號時SC積分器80的開關SW1〜SW4之狀態的圖。 ίο 第五圖（a)、（b)為表示生成驅動信號的降壓期間 中的信號時SC積分器80的開關SW1〜SW4之狀態的圖。 第六圖（a)、（b)為通過SC積分器80所生成的驅 動信號之一例。 16 1293124 【主要元件符號說明】 1磁通量閘門磁力計 Η、12、13磁感測器 111、12卜131磁性體鐵心 5 112、122、132勵磁線圈 113、123、133檢測線圈 21勵磁側開關電路 22同相放大器 23反相放大器 ίο 24D/A變換器 25 DAC控制塊 31檢測側開關電路 32電壓調整電路 33差動放大器 is 34磁滯比較器 35計數器 41控制電路 411記憶體 51控制線 2〇 61匯流排 71微型電腦 17BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal detecting circuit of a magnetic sensor, and more particularly to a signal detecting circuit for providing a magnetic sensor having high precision and stability. 5 [Prior Art] There is a well-known so-called magnetic flux gate magnetometer that periodically charges a magnetic flux by inputting a periodic drive signal to an exciting coil wound on a soft magnetic core (c〇re), according to correspondence The intensity of the external magnetic field is measured by measuring the saturation time interval at which the magnitude of the magnetic field of the outer 10 parts of the object changes. The magnetic flux gate magnetometer has various excellent features as a magnetometer: (1) high sensitivity and magnetic field resolution, (2) ability to measure weak magnetic fields, (3) wide measurement range, and (4) magnetometers in other ways. Compared with temperature stability, (5) high linearity to the input magnetic field. 15 As an example of such a magnetic flux gate magnetometer, Patent Document 1 discloses that a magnetometer "having an energization of an alternating current signal applied to an exciting coil" excites a toroidal core composed of a magnetic detecting material to saturation. The magnetic zone's magnetic sensor uses a symmetry of the saturation magnetic flux density excited in the toroidal core to measure the magnetic flux density. Further, Patent Document 2 20 discloses that an excitation current is applied to an exciting coil of a magnetic flux gate formed by winding an exciting coil and a detecting coil in an iron core by an oscillator, and the output of the detecting coil is synchronized by synchronizing the whole and the electric power. A magnetometer that rectifies and outputs. Recently, I am looking forward to using it in small machines such as magnetic sensors for portable compasses. 5 1293124 The output signal detection circuit of the detection coil of the magnetic sensor of the magnetometer is given. In addition, it is performed in the direction of a plurality of spatial axes; 疋 Usually, a plurality of magnetic flux gate magnetometers are used in combination, and the deviation of each magnetic force is small. It does not occupy the area of the wafer when it is integrated. [Patent Document 2] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. It is to provide a detection circuit with stability and small manufacturing deviation and a saddle/shoulder accumulation degree. The signal of the magnetic sensor that is small enough to be used for the purpose of the invention is to be invented. It is a signal detection circuit of the sensor, which is characterized by the detection of the sensor. The differential amplifier of the output voltage of the coil; the comparison is crying ^ is input to the output of the county reducer, and the output is between the voltages of the (4) phase __ spikes included in the voltage divided by the two, and the digital value of the logic value is taken. a signal; and a counter that counts the number of pulses of the clock in the comparison - the obtained - square logical value _. - Round out = Sample 'The magnetic detection signal of the present invention. The signal detection circuit counts the number of pulses of the clock, and the New Zealand detection line = the time contained in the pen pressure. (4) The time of the two adjacent Qianlongs ^ 20 1293124 Enables high-precision magnetic field measurement. In addition, by using a counter instead of the analog circuit, it is also possible to perform measurement in a short time. In addition, the magnetic == electric discharge mill immediately touches the digitizer of the comparator, so it is difficult to influence the noise or noise. In addition, the amplification of the output voltage is made by the differential 5, so the common-mode noise is one... Zhongjing wants to invent it--is a kind of signal detection circuit based on the magnetic sensor described in the 1st. The 圏 phase connection 'selecting the above-mentioned 15 迕 迕 成为 成为 检测 检测 检测 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够 能够[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail as an embodiment of the present invention, and a configuration shown in the sr circle. The magnetic flux shown in the figure is the closing magnetic force γ axis, three magnetic sensors of each axis; the sensors U, 12, U pass through the dip 12, 13. The magnetic core 1U, the two-crystal soft magnetic material, and the like 121 and 131 made of these magnetic soft magnetic materials are wound around the magnetic coils 112, 122, and 132 and the detection coils 113, 123, and 133. The exciting coils m, m, and 132 are controlled by a mechanism including an excitation side switching circuit 2, a non-inverting amplifier 22, an inverting amplifier 23, an inverter 24, and an operation of controlling the D/A converter 24. The excitation coil 25) is driven by an excitation coil drive circuit. In addition, the output voltages of the detection coils 113, 123, and 133 are processed by a signal detection circuit, and the lung number detection f path includes a detection side_circuit 3A, and a voltage adjustment circuit that adjusts the output voltage to a given voltage level. 32. A differential amplifier 33 that amplifies an output voltage, a hysteresis comparison of a digital signal that outputs a low (L0W) level during a period between two spike-like (1) voltages included in an output voltage, and The counter % of the number of pulses of the clock signal in the period in which the digital signal outputted by 34 (34) is low level is counted. >, the circuit 41 controls the DAC control logic 25. The control circuit 41 receives the count value of the person input by the hacker 35 and stores it in the internal memory 丨5 411. The control circuit 41 is connected to the excitation side switch circuit 21 and the control line 5 of the detection #contact circuit 31. The control circuit 41 controls the on and off of the switch 21 money switch 31 via the control line 51. The control circuit 41 is connected in communication with the microcomputer 71 (external device), and the count value stored in the L-body 411 is appropriately transmitted to the microcomputer. 20 is a daily sequence diagram showing the operation of the magnetic flux gate magnetometer 1 of the present embodiment. Next, the operation of the magnetic flux gate magnetometer 1 will be described based on the timing chart shown in the figure. In the following description, all the contacts of the excitation side switch circuit 21 and the depression circuit 31 are previously turned on (opened). 8 1293124 As shown in the second figure, the start signal (8) is first input from the microcomputer 71 via the bus bar 61 to the control circuit 41. After inputting the measurement start signal, the control circuit 41 next rotates a signal for turning on the contact of the excitation side switching circuit 21 and the detection side switching circuit 31 with the X axis (hereinafter referred to as 5 for the X-axis selection signal). ) (t2). After the input of the X-axis selection signal, the excitation-side switching circuit 21 and the detection-side switching circuit 31 connect the contact of the exciting coil 112 and the detecting coil φ Π3 for measuring the magnetic field in the direction of the x-axis. through. Thus, the excitation side switch circuit 21 selects the excitation coils 112, ίο 122, 132 that carry the drive signal p and the drive signal N, which will be described later. Next, the control circuit 41 outputs a drive enable enable signal (t3) to the DAC control logic 25. After the DAC control logic 25 is input with the drive start enable signal, the DAC data is input to the D/A converter 24. Specifically, first enter the down count data as the DAC resource (t4~t5). By the countdown data, the signal for preventing the high-voltage counter electromotive force which is generated by the φ in the exciting coil 112 from being damaged to the circuit elements such as the in-phase amplifier 22 and the inverting amplifier 23 is loaded immediately before the boosting period to be described later. Next, the DAC control logic 25 outputs the upc〇unt data as DAC data to the D/A converter 24 (t5). Thus, the signals (t5 to t8) of the boosting period of the triangular wave are output from the D/A converter 24. Next, the DAC control logic 25 stops the output of the positive data of the D/A converter 24 in t8, and outputs the countdown data this time. Thus, the signal (t8 to ul) of the step-down period of the triangular wave is output from the D/A converter 24. Next, the DAC control logic 25 stops the output of the countdown data to the d/a converter % 9 ! 293124 in t11, and outputs the positive data. By the countdown data, the signal for preventing the high-voltage counter electromotive force generated in the exciting coil from being damaged to the circuit elements such as the in-phase amplifier 22 and the inverting amplifier 23 is loaded immediately after the above-mentioned pressing period. The drive signal of the D/A converter 24 is supplied to the non-inverting input terminal of the non-inverting amplifier 22. The Vref signal of the D/A converter 24 is supplied to the non-inverting input terminal of the inverting amplifier 23. The inverting input terminal of the non-inverting amplifier 22 is negatively fed back to the output of the in-phase amplifier 22. Further, the inverting input terminal of the inverting amplifier 23 is input to the output of the non-inverting amplifier 22. Thus, 10 outputs a signal indicated by a solid line (hereinafter referred to as a drive signal P) in the second diagram in which the output signal of the D/A converter 24 is amplified from the non-inverting amplifier 22, and further, from the inverting amplifier 23 A signal indicated by a broken line in the second diagram in which the amplitude of the drive signal P is inverted is output (hereinafter referred to as a drive signal N). The drive signal P output from the non-inverting amplifier 22 is loaded into one of the two terminals of the exciting coil 112. Further, the drive signal N output from the inverting amplifier 23 is loaded to the other of the two terminals of the exciting coil 112. Therefore, the excitation coil 112 is loaded with a differential voltage of the drive signal P and the drive signal N (hereinafter, this voltage is referred to as an excitation voltage). 20 As shown in the second figure, the spike-like voltage (t7, t10) generated between the terminals of the detecting coil 113 is based on the B-H curve (b: magnetic flux density, H: magnetic field) of the magnetic sensor n. The voltage of the electromotive force generated in the unsaturated interval. The time interval (Τχ) of the two peak-like voltages in t7 and t10 changes in accordance with the external magnetic field Δ11 loaded in the magnetic sensor 11. Also, by measuring the time interval (Τχ) at which two peak-like voltages are rotated, it is possible to obtain information on the intensity of the external magnetic field ΔΗ and the like. "The spike-like voltage generated in the coil 113 is exchanged to a predetermined level by the voltage adjusting circuit 32, and then input to the differential amplifier 33:5 and amplified. The output voltage amplified by the differential amplifier 33 It is input to the hysteresis comparator 34. The hysteresis comparator 34 outputs a low level during the period in which the adjacent pointed voltages included in the output voltage are clamped, and is high in the other period (fgh Level digital signal. In the initial state, the hysteresis comparator "transforms 1 〇 ^ = 甩 flat. Thereafter, the hysteresis comparator 34 starts the output of the low level (t7) when the spike voltage due to the polarity inversion of the exciting voltage in t6 is input. Further, the hysteresis comparator 34 cuts the output high level (t10) when a spike-like voltage due to the polarity inversion of the excitation voltage in (5) is input. The digital signal output by the magnetic enthalpy than the parent state 34 is input to the counter 35. The § decimator 35 is input with a clock signal, and the counter 35 counts the number of pulses of the clock signal during the period in which the digital signal output from the hysteresis comparator: 34 is at a low level. The digital signal goes high, and after the pulse number is completed, the counter 35 outputs the count value to the control circuit 41. The control unit 20 41 stores the input count value in the memory 411. Next, the control circuit 41 turns off the dynamic start enable signal input to the DAc control logic 25 (tl3). Further, the control circuit 41 stops the input (U4) of the spindle-side hammer circuit of the excitation-side switching circuit 21 and the detection-side switching circuit 31. In this way, the contact 乂 and the control circuit 41 of the excitation coil U2 and the detection coil 113 for measuring the magnetic material of the material 2: 2,123,124 are used to electrically switch the excitation side switch to Y1 (t5). By starting the processing of the Y-axis performed during the period of the γ-axis in the γ-axis, the processing of the ί axis performed during the period of XNEW == r°M and tl7 to t18 is also It is the same as the case of the χ axis. Surprise Ζ After the above operation, the X-axis, γ #, and 7 memory are 4U, and the history is followed: the averaging values of the two-axis and Z-axis are saved to the interrupt of the writing completion. The transmission from the Γn circuit 41 will notify the passage of the count value, and the read request is transmitted by 彳. The eight sides H of the body 4n are stored in the memory of the control circuit 41: the strength measurement of the outer ^ 15 . _, Tixian material magnetic field Δ Η Η Η : : : : : : : : : : : : : : : : : 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月 月The signal used to drive the excitation line m. Therefore, in comparison with the emotional ratio of the Laiby circuit, ί = 1, Γ generates a highly accurate and stable drive signal: in addition, the deviation can be suppressed by using the digital circuit. Further, in the magnetic flux door magnetometer i of the present embodiment, the plurality of excitation=rings 112, 122, and 132 are driven by the same D/A converter 24. Therefore, it is possible to carry a uniform excitation power to the exciting coils 112, 122, and 132, respectively, and 12 20 1293124 = deviation of the rotation. In addition, by making the circuits common, it is possible to reduce the number of components and the area of the wafer in the case of integration. "In addition, the magnetic flux gate magnetometer 1 of the present embodiment can increase the length of the step-up period (6-turn) of the drive number and the step-down period (t8 to til) with high precision by using a number of circuits, thereby improving the measurement. Accuracy. If necessary, in order to correct the influence of the erroneous sounds and/or the gaps included in the time interval (Tx, Ty, Tz), it is necessary to measure the length of the entire drive signal in the case of the analog circuit. , month b 1 is a small-sized and low-power magnetic flux door magnetometer 1. In addition, the magnetic flux gate magnetometer 1 of the present embodiment measures two spike-shaped electric power by counting cry = day ==__ row count ' Compared with the case of using analog circuit, it is sufficient to measure the accuracy. In addition, the time interval (TX, Ty, Tz)... 丨 丨 μ 舰 舰 舰 舰 7 15 15 15 15 15 15 15 15 15 Β In the case of the generalized, the a/d converter with a large area occupied by the integrated solar disk has a small area occupied by the azure magnetometer i. °°, and this is enough for a small magnetic flux. Idle gate (Tx, Tbu y, t = wave and filter combination time The gap accuracy requires a silk scarf, and the gorge is carried out in (10) in order to increase the measured value. In addition, this also suppresses the magnetic flux gate magnetometer comparator 33 of the present embodiment to pass the detecting coil U3 123. The output voltages of the magnetic spaces 113, 123, and 133 are digitized in the early stage 13 1293124, and thus are hardly affected by temperature or noise. Further, in the magnetic flux gate magnetometer of the present embodiment, the plurality of detecting coils 113, 123, The processing of the turn-off voltage of 133 is performed by the same differential amplifier 33 and the same hysteresis comparator 34. Therefore, the variation of the measured values between the five detection coils 、3, 123, and 133 is small. By using the same circuit to detect the output voltages of the coils 113, 123, and 133, the number of components and the area of the wafer can be reduced during the integration. "In addition, the magnetic flux gate magnetometer of the present embodiment. In the case, the amplification of the output voltage 10 uses the differential amplifier 33, so that the common-mode noise (the hair y 7 _F / 彳 long) is less mixed. In addition, the detection coils 113, 123, The grounding of the common mode noise can be suppressed by the above. However, an embodiment of the present invention has been described in detail above, but the description of the above embodiments is merely for facilitating the understanding of the present invention, and does not constitute the present invention. The present invention can be modified and improved without departing from the gist thereof, and the present invention also includes equivalents thereof. For example, a low-pass filter can be provided at the rear of the D/A converter 24, and the inverter 24 can be provided. The output drive signal is smoothed. Further, the generation of the drive signal can be generated instead of the D/a converter 24, 2, for example, by a Sc (switched capacitor) integrator composed of the structure shown in the third figure. The SC integrator 80 shown in the figure is composed of four switches SW1 to SW4, a capacitor C1, and an integrating circuit 81 using an operational amplifier. The switch SW capacitors cn and SW4 are connected in series, swi is connected to the DC power supply vin, and the output of SW4 is input to the inverting input terminal 55 P1 of the operational amplifier constituting the integral 14 1293124 circuit 81. A switch SW2 whose one end is grounded is connected between them. Capacitor crying C1 sen Off SW4 is connected to the switch SW3 with grounding. w 讦 〇 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在 在The interaction becomes the state shown in the fourth figure U), (1). By this t, as shown in the figure (figure u), it is possible to obtain the slope of the slope, and drive the "number. In addition, in the case of the sign in the step-down period in which the drive signal is generated, the switches SW1 to SW4 The on-off is performed at a predetermined interval At2 (butterfly drive mode), and the interaction becomes a state shown in the fifth diagrams (a) and (b). Thus, as shown in the sixth diagram (b), The drive signal that is stepped down in a stepped manner at a constant slope, and the drive signal output from the SC integrator 80 is passed through the low-pass filter and smoothed, whereby a linear drive signal can be obtained. In the case of using a well-known digital circuit, it is possible to accurately match a ti and Δί2, and it is possible to generate an accurate triangular wave whose height is consistent with the slope of the step-down period during the step-down period. Therefore, even when the SC integrator 80 is used, Also in the same manner as in the case of the D/A converter 24, a magnetic flux gate type magnetometer 1 capable of performing magnetic field measurement with high precision can be realized. 15 20 1293124 [Schematic Description of the Drawing] The first figure shows an embodiment as the present invention. get on FIG. 2 is a timing chart showing the operation of the magnetic five-flux gate magnetometer 1 described as an embodiment of the present invention. The third diagram shows the operation of the magnetic five-flux gate magnetometer 1 as an embodiment of the present invention. A diagram of an example of the SC integrator 80 described in the first embodiment. • The fourth diagrams (a) and (b) show the states of the switches SW1 to SW4 of the SC integrator 80 when a signal in the boosting period in which the drive signal is generated is generated. (a) and (b) are diagrams showing the states of the switches SW1 to SW4 of the SC integrator 80 when a signal in the step-down period in which the drive signal is generated is generated. Fig. 6(a), (b) An example of a driving signal generated by the SC integrator 80. 16 1293124 [Description of main component symbols] 1 magnetic flux gate magnetometer 12, 12, 13 magnetic sensors 111, 12 128 magnetic core 5 112, 122, 132 excitation coil 113, 123, 133 detection coil 21 excitation side switching circuit 22 non-inverting amplifier 23 inverting amplifier ίο 24D / A converter 25 DAC control block 31 detection side switching circuit 32 voltage adjustment circuit 33 differential amplifier is 34 magnetic Hysteresis comparator 35 counter 41 control 51 controls the memory circuit 411 2〇 line 61 busbar 71 Microcomputer 17